Caption: Nerve synapse, computer artwork. A synapse is a junction between a nerve cell (or neuron, centre right, more in the background) and another cell (lower right). During the transmission of a nerve signal, the electrical impulse in the neuron causes vesicles (clear spheres) in its tip (or bouton) to burst, releasing neurotransmitter chemicals (orange) into the gap (synaptic cleft). These bind to receptors (red) on the second cell. This carries the signal to the second cell. Several types of cell have synaptic receptors, including muscle cells, neurons and glandular cells. The boutons are specific to neurons, however.